This make the variable purpose more clear.

silence to 0 when the end of the string is reached

of the tune to repeat it

- Start tone_alrm driver after uorb
- Replace tone_alarm $TUNE_ERR with tune_control play -m ${TUNE_ERR}
- TUNE_ERR is a string

untested on real hardware

return -EINVAL

Now it is possible to set a string and a control.
The get_next_tune function use the same return values as the erliaer
implemented parse_cmd and parse_string functions.

minor changes

to allign with the libray output which is in us

cmake configs: Modify to include new library

 - the actual corrected rates currently used by mc_att_control are not
   logged